Carbon black manufacture



Jan. 17, 1956 R. G. ATKINSON 2,731,328

CARBON BLACK MANUFACTURE Filed May ze, 195o F /G. 2. U ATTORNEYS UnitedStates Patent O CARBON BLACK MANUFACT URE Robert George Atkinson,Bartlesville, Gkla., assiguor to Phillips Petroleum Company, acorporation of Delaware Application May 29, 1950, Serial No. 164,878

5 Claims. (Cl. 23e-209.4)

This invention relates to the manufacture of carbon black. In oneembodiment it relates to the conversion of low-grade carbonaceousmaterials to carbon black. ln another embodiment it relates to theutilization of a contiguous mass of flowable particulate solids in themanufacture of carbon black. invention relates to the manufacture ofcarbon black from a gas comprising carbon monoxide.

As is well-known in the art, carbon black has utility in various fields,particularly in the compounding of natural and synthetic rubbers.

I have discovered a process for the manufacture of a carbon black havingspecial utility in the lield of rubber compounding. Carbon blackmanufactured by the process of my invention, when compounded withnatural or synthetic rubber, imparts excellent reinforcement characvteristics to the iinished stock, particularly as regards resistance ofthe finished rubber to abrasion.

My invention is concerned with the utilization of lowgrade carbonaceousmaterials, such as pulverized coal, pitch, petroleum residua, gas oils,fuel oils, and the like, in the manufacture of carbon black, and inelecting such a process in conjunction with a moving contiguous mass ofiiowable solids, generally pebbles utilized in conjunction with amodified pebble heater system.

The term pebble, as used throughout the speciiication,

denotes any solid refractory material of iiowable form and size that canbe utilized to transfer heat from one zone to another. Pebbles arepreferaby substantially spherical and about (9,2 inch to l inch indiameter, a preferred range generally being from about /4 to 1/2 inch.Pebbles are formed of a refractory material which will withstandtemperatures at least as high as the highest temperature attained in thepebble heater system, and must be capable also of withstandingtemperature changes within the system. Refractory materials, such asmetal alloys, ceramics, or other satisfactory materials, may be utilizedto form pebbles. For example, ceramics, alumina, periclase, thoria,beryllia, and mullite may be satisfactorily used to form such pebbles,or may be used in admixture with each other or with other materials.Pebbles formed of such materials, when properly fired, serve very wellat high temperatures. Some pebbles withstand temperatures up to about3500 F. Pebbles which are used may be either inert or catalytic, asdesired.

A pebble system of the type referred to hereabove generally comprises aseries of substantially vertically extending zones, often in' verticalalignment with each other, and connected by relatively narrowinterconnecting zones or throats. Generally, the top or upper zone isemployed as a pebble heating chamber, and the succeeding lower zones asconversion zones, cooling zones, or the like, as required in the specicprocess. A combustion zone or chamber is positioned adjacent or in closeproximity ,to the sides of the lower portion of the heating chamber, andcombustion gas formed in the combustion chamber is passed through themass of cooler pebbles in heat exchange relation therewith, in thepebble heating In still another embodiment this 'I fce chamber. A hotgas source other than a combustion chamber is sometimes employed. Acontiguous mass of particulate contact material, such as pebbles, llsthe pebble heating zone, and each of the succeeding zones, together withthe interconnecting zone or throats, and flows downwardly through thesezones by gravity. Pebbles are discharged from the bottom of thelowermost zone of the series at a controlled rate, and returned, usuallyby elevating means, to the inlet in the upper portion of the pebbleheating zone.

Pebble heater apparatus is generally employed in the thermal treatmentor conversion of hydrocarbon materials. Operation of such a pebbleheater system generally involves circulating a contiguous pebble massthrough e entire series of pebble zones, including the interconnectingthroats. That portion of the pebble mass descending through the heatingchamber is heated to a suitable predetermined temperature above adesired treating or conversion temperature n heat exchange relation witha combustion gas or other hot gases from any desired source. Pebbles areoften heated in the heating chamber to temperatures as high as from 2000to 3000 F. and in some cases higher, dependent upon the temperaturerequirements of the subsequent treating step or steps. The pebbles thusheated are contacted directly with one or more materials to be treatedin one or more zones of the pebble heating system under suitable timeand temperature conditions to elfect the desired treatment. The pebblemass, having given up heat to the material or materials treated,descends through the bottom of the lowermost chamber and is fed to anelevator for further handling, generally for transfer to an inlet at thetop of the pebble heating chamber for reheating and recirculationthrough the system.

In a modified pebble heater system of my invention, I cool pebbles in apebble cooling chamber, and control an exothermic reaction taking placein a pebble chamber downstream from the pebble cooling chamber. Pebblesin the downstream chamber, although they transfer an amount of heatnecessary to initiate an exothermic reaction therein, absorb exothermicheat thus liberated in a manner to control the temperature of thatexothermic reaction to a desired level, at which level maximum yields ofdesired carbon black product are obtained.

An object of my invention is to provide for the manufacture of carbonblack.

Another object is to provide for the utilization of lowgradecarbonaceous materials in the manufacture of carbon black.

Another object is to provide for the utilization of a modified pebbleheating system in the manufacture of carbon black from a gas comprisingcarbon monoxide.

Another object is to provide for the manufacture of carbon black fromcarbon monoxide at a temperature below 1200 F.

Other objects will be apparent to those skilled in the art from theaccompanying discussion and disclosure.

ln accordance with one embodiment of my invention, a low-gradecarbonaceous material is burned at a high temperature in the presence offree oxygen to produce carbon monoxide as a combustion product. Theresulting combustion product is then quickly quenched to stabilize thecarbon monoxide concentration therein, i. e., to quickly cool it to atemperature below which the wellknown water gas shift equilibriumCO-I-HzOCOz-l-Hz can extensively take place to the CO2 side. Suchtemperatures are preferably below 1200" F., and in any event are lowerthan 1600 to 1800" F. The quenched cornbustion gas is then contactedwith pebbles in a conversion chamber under conditions causing carbonmonoxide in the combustion gas to react exothermically to form carbonblack, and carbon dioxide as a lay-product, as iles lustrated by theequation ZCOC-l-COz, and to a somewhat lesser extent to form carbonblack, and water as a byproduct; as illustrated by the equation,

CO-l-Hz-'C-i-Hz@ such conditions being regulated to provide for anabsorption of the liberated Aexothermic heat of reaction by the pebbles,'and for controlling the exotherrnic reaction temperature to a levelproviding for maximum yields of carbon black. I have found ,that inconducting the reaction in the conversion chamber at 'a temperaturebelow 1200 F., more preferably from 900 to 1100 F., carbon black isproduced from carbon monoxide Tin, a maximum yield, and that if `suchtemperatures exceed 1200c the yield of ycarbon black is rapidlydiminished. Removal of exothermic heat in :accordance with Vthisinvention permits the reaction to `occur at a temperature level morefavorable .for the `formation `of carbon black from carbon monoxide. Itis therefore an important object 'of'my invention to effect `such a'conversion 'a't a temperature :belowabout l200 F.

The relative rates "of flow of gases and pebblesthrough 'the conversionchamber are dependent to a large zextent -on the concentration of carbonmonoxide in Vthe gas inuen't to the conversion chamber, and the specificheat of the influent pebbles thereto. Generally, however, vthe specificheat of `pebbles manufactured from 'ce1-amies, alumina, 'or the like,i'. e., non-catalytic materials 'of the type `discussed hereabove, issuiciently'high and 'the 'content of the carbonmonoxide inthe influentgas is `in such a range that when introducing pebblesand gas intotheconversion chamber such an introduction is effected so as to maintaina weight ratio yof influent pebbles to linfluent gas within the limitsoffrom about 8:1 to 15:1. yMore generally, 'the `specific heat of thepebble material is within therange of from '0.2 to 0.3, and the 'carbonAmonoxide content of the influent gas will be within 'the "limits of 40to `70 per cent, `often from 50 to 60 per cent. For exlample, 'when thespecific heat of Vthe pebble influent material is 0.25, and the carbonmonoxide content of the influent gas is about 50 percent, an exothermic`reaction temperature V,of about 1000 F. can be 'maintained whenintroducing Vpebbles into the conversion chamber in a weight ratio toinfluent gases of 11:1.

YReference is made to the drawings, "Figures land 2, each illustrating7preferred embodiments of the process of my invention. VIt is to beunderstood that these figures are diagrammatic and `may be alteredinfm'any respects by those skilled in the art, `and yet 'remain 'withinthe intended scope of `my invention. Figure l is illus- 'trative Yof oneVforni of my invention, wherein'a hydrocarbon oil is burned to form acarbon monoxide-containing combustion ga's mixture which is thencontacted con- "currently With a downwardly {iov/ing mass `of .peb ble'sunder controlled conditions to produce 'carbon black. Figure :2Aillustrates anotherembodiment 'similar to Vthat of Figure "l, exceptthat the'flowof carbon r'nonoxid'econtaining gas influent is maintainedin countercurrent flow relation with pebbles descending througha'converiontchamber.

With reference to Figure l, fuel oil from line 10 is lintroduced withoxygen from line 11, of commercial grade Ypurity,i. e..90 to 95 per centor higher, together vwith a recycle stream from line 12 comprising 'amixture 'of carbon dioxide 4and hydrogen described hereafter, intocombustion chamber 13 and burned therein, -in proportions to producecarbon monoxide in high yield. The mol ratio of oxygen to hydrocarbonintroduced into chamber 13 is regulated to provide a combustiontemperature preferably within the limits of 2000 to 3000 F., more often`2000to 2500" E., under which conditions -carbon VIn'orit'fxicle isform'edin-iigh yield. 'Theoptimum atioof oxygen to-jhydfocarbon`utilized is Idependent,of `chou'r's'e, on 'the specific hydrocarbonbeinguburned. However, Ithave lfoun'clthata combustionAtemperature'within the lil in g the'inucnt gas, heat t ecftheinEuentgaS, and on the ratio of Vrpebble feeder Ameans jin line 33,

limits of 2000 to 2500 F. can be obtained when burning a hydrocarbon oilwith oxygen, in an atomic ratio of oxygen to carbon in the oil withinthe limits of about 106:1 to 1.2211. Under these conditions, carbonmonoxide in high yield is present in the combustion product in a volumeratio to hydrogen of about 1:1, or slightly less. To effect thecombustion at a temperature of from 2500 to 3000 F., an atomic ratio ofoxygen to carbon in the oil within the limits of 1.2211 to about 128:1is employed. For example, when charging a combined feed consisting of100 pounds of a Vfuel oil preheated to l00" F., 1500 cubic feet ofcarbon dioxide, 1700 cubic feet of oxygen, and 2500 cubic feet 'ofhydrogen per unit time into chamber 13, the temperature of the burningreaction is 2400 F., and vthe combustion gas formed contains on a molbasis, per cent carbon monoxide, 7 per cent carbon dioxide, 36 per centhydrogen, and 17 per cent steam.

Etiiuent combustion 'gas from chamber 13 is withdrawn through line ifi,and is 'quenched in direct `heat exchange with water introduced intoline 1d from line 16. Quenched combustion gas is passed from line 14into indirect heat exchange with a cooling fluid in cooling zone 17.Cooling in zone 17 is effected so that the temperature of cooledeffluent therefrom is within the limits of from to 200 F. Etiluent gasfrom vchamber 17 is discharged through line 21 into water trap 22,wherein water is separated, and then discharged from zone 22 throughline 23. Cooled combustion gas in zone 22, freed of water, is dischargedthrough line 242- into carbon dioxide removal system 26, which can beany desired means for removing carbon dioxide. One Well-known method isthat of absorption of carbon dioxide from the gas by contacting samewith an aqueous alkanol amine, as for example, monoethanol amine.Combustion gas, freed of carbon dioxide, is discharged from lzone 26through li e 27 into an upper portion of a gas conversion chamber 2S ofa pebble heater apparatus, and passed throughchamber 2S concurrentlywith a mass of pebbles gravitationally introduced into chamber 28 from a-pebble cooling chamber 29 disposed above chamber 2d.

The temperature'of the influent gasinto chamber 28 from zone 26 isdependent on the specilic carbon dioxide removal step utilized. Whenconventional aqueous al- Ikanol amine absorbents are employed, thetemperature of influent gas to Zone 2d is generally within the limits offrom about to 150 F. Pebbles cooled from a ternperature of about 1000 to1200 F. to a temperature within the limits of about v300 to 700 F., asdescribed hereafter, are passed from chamber 29 into chamber 28 throughthroat 3l. Upon contact of influent gases with pebbles in zone 28, thatgas is heated to a temperature at 'which'carbon monoxide thereininitially reacts exothermically to form carbon black. rhe peobles, uponcontactgas as already mentioned, and the heatcapacity ofthepebbles-suppressesexcessive temperature rise so that thereacting gas,i. c., carbon monoxide, does not reach aternperature that is unfavorableto `the production of carbon black in maximum yield. Accordingly,pebbles and total gaseous eiuent'discharged Afrom zone 28'are at atemperature'below 1200 F., and preferably in Vtherange of about 900 to1l00 F.,depend lent upon the temperature of the influent pebbles andpebbles to gas introduced into lthe conversion chamber. vPebbles andgaseous etliuent' are discharged from zone 28 through line 32 into'pebble separation zone 33 at a temperature of about 900 to l100 F.,although in some cases that temperaturewill be as high'as 12.00 F. Bygaseous eluent, I mean to'include total effluent gas from chamber 28containing suspended carbon black product. The rate of pebble tiowfromlon'e 23 is nregulatedby anysuitable u suchfas star valve 4vitt).t'llowfrom 'zone Vv'28 via line'SZ to Lione 33 ca'nbe facilitated byby-passline '145 containingvalve.

Gas eftiue around feeder 40. Pebbles are removed from zone 33 and passedby elevating means 34 into chamber 29 kat theirfexisting temperaturewhich generally approximates about 1000 F., as already discussed. Totalgaseous effluent is cooled by admixing therewith a stream comprisinghydrogen and carbon dioxide from line 36, previously cooled to atemperature as low as 100 F. or lower, as described hereafter. Thegaseous admixture thus formed is passed from zone 33 via conduit 37 intocarbon black separation means 38, generally a system of bag filters ofthe type well-known in the art for separating suspended solids fromgases. Ei'liuent gas in line 37 is passed through cooler-condenser zone41 and cooled therein as desired, preferably to condense steam formed asby-product in chamber 28. Steam condensate thus Vformed is removed fromzone 41 through line 43. Gases, substantially water free, comprisingcarbon dioxide and hydrogen containing carbon black suspended therein,are passed from zone 41 via line 42 to zone 38. In some cases the amountof by-product steam formed is so small that its presence can be ignored,and in such a case, gases in line 37 can be passed directly to zone 38,or first cooled as desired in zone 41 without condensing by-productsteam. In any event, the temperature of the gaseous stream admitted intozone 38 when utilizing bag filters therein is preferably below about 400F. for the reason that higher temperatures are not easily withstood bysuch type equipment. However, dependent upon the type of carbon blackseparation means employed in zone 38, the temperature of gaseousintroduced thereinto from line 37 may be varied accordingly. Carbonblack is filtered from the inliuent gases to zone 38 and withdrawn fromzone 38 through line 34. Residue gas separated in zone 38 is dischargedthrough line 46. Residue gas in line 46 comprises hydrogen and carbondioxide and is passed in at least a major proportion from line 46through line 47, cooler 48, and discharged from cooler 48 into line 49.Gas in line 49 is cooled to a temperature as low as from 100 to 200 F. Aportion of the gas in line 49 is passed through line 36 into pebbleseparation means 33 to cool gaseous eiuent therein, as alreadydescribed.

A remaining portion of cooled gas in line `49 is passed through -line 51into the lower portion of chamber 29 in countercurrent tiow togravitationally moving pebbles introduced thereinto by elevating means34 at a temperature approximating 1000 F., as already discussed. Gasfrom line 51 is passed in countercurrent liow relation with pebbles inzone 29, and in heat exchange therewith to cool the pebbles to atemperature within the limits of about 300 tof700 F. for utilization inchamber 28. Residue L.

gas thus heated in zone 29 is discharged therefrom through line 52 andpassed into line 12 for utilization in the burning step, alreadydiscussed.

Any residue gas in the line 46 not passed into zone 48 is passed throughline v54 without any additional cooling and recycled through line 12into chamber 13. Any desired proportion ofi gases in line 12 can bewithdrawn through line 53.y This is particularly.advantageous withrespect to removing nitrogen from the system, introduced as an impurityin the oxygen, through line 11.

In one embodiment of my invention, as illustrated -in Figure 1, I preferto direct the flow of gases from pebble separation zone 33 into line v37by maintaining a back pressure lin chamber 29 greater than the pressuredrop through chamber 38. This can be done by regulating valve 56 in line52. Accordingly, at times there may be a slight iiow of carbon dioxideand hydrogen through elevator 34 in a direction toward chamber 33. Inthis manner, pebbles are efliciently separated from carbon black productadhered to their surfaces, and from other product gases. Any gas thusreturned to zone 33 from Azor'ie 29'can, be'passed ,from zone38 throughlines 54 and 12 to chamber 13.

l Referring to Figure 2, a contiguous mass of pebbles is gravitationallypassed through combustion gasy quench imatng 1000 F., as describedhereafter.

chamber 61, pebble cooling chamber 62, and conversion chamber 63. Acontiguous mass of pebbles thereby lls chambers 61, throat 64, chamber62, throat 66, chamber 63, and pebble outlet 67 in the lower part ofchamber 63. In this embodiment, pebbles are discharged from chamber 63into elevating means. 68 through line 67 at a rate controlled by meansof star valve 69. The combustion of the fuel oil with oxygen and acarbon dioxide-hydrogen recycle stream in chamber 13 is the same as thatdescribed with respect to Figure l. Effluent combustion gas dischargedfrom chamber 13 at a temperature within the limits of 2000 to 3000 F. isquickly quenched by passing it in heat exchange relation with pebbles inquench chamber 61, introduced thereinto at a temperature approx- Gasesleaving chamber 61 are quenched to a temperature preferably below 1200JF. and in any case lower than from 1400 to 1800 F. in order to maintaina maximum concentration of carbon monoxide in the quenched gas. Forexample, when burning a mixture of fuel oil, oxygen, and recycle gasfrom line 12, in the proportions related in the discussion of Figure l,eiiiuent combustion gas in line 14 is at a temperature of 2400 F., andpassed through chamber 61, it emerges at a temperature of 1100 F.,

t a total of about 270,000 B. t. u.s having been absorbed in the quenchstep. Pebbles in chamber 61 are heated as a result ofthe heat exchangerelation therein, and passed downwardly through cooling chamber 62. Forexample, in the specific quench discussed above, pebbles enteringchamber 61 at 1000 F. are passed through throat 64 at a temperature ofabout l220 F. In order to utilize pebbles discharged from chamber 61 inconversion charnber 63 inA a manner similar to that in chamber 2S ofFigure 1, it is necessary to cool the pebbles to a temperature below1200 F., and preferably within the limits of from 300 to 700 F.,although in some cases higher temperatures may be utilized. Pebbles at atemperature approximating 1200 F., in chamber 62 are cooled bycontacting the pebble mass in direct heat exchange relation withrelatively cool steam, or any desired inert cooling gas at apredetermined low temperature suiiicient for eifecting the necessaryamount of heat transfer. Relatively cool steam is introduced intochamber 62 through line 60. Steam is withdrawn from chamber 62, throughline 65. In the example discussed immediately above, when passing 1540pounds of steam through chamber 62, in at 320 F., the temperature of thepebble mass discharged through throat 66 is about 780 F., and steam isdischarged at 1000 F. Chamber 62 provides therefore a means forcoolingpebbles previously utilized for quenching combustion gas, and also forproviding super-heated steam for any desired utilization outside theprocess system. Pebbles thus cooled in chamber 62 are passed downwardlythrough chamber 63.

Gaseous effluent is discharged from quench chamber 61 through line.71and cooled in direct heat exchange relation with water from line 72 inline 73 to a temperature as low as from 100 to 200 F. The resulting cooladmixture in line 73 is passed into water trap 74, wherein water isseparated from the gas and then discharged from zone 74 through line 76.Gas thus freed of water is passed from zone 74 through line 77 to carbondioxide separation means 26 of the type discussed hereabove. Carbondioxide is separated from the gas in zone 26, and discharged throughline 25. Combustion gas freed of carbon dioxide and water, andcomprising carbon monoxide and hydrogen, is passed from zone 26 throughline 81 into chamber 63 atv a point in the lower portion thereof. Gas inline 81 is introduced into conversion chamber 63 at a temperatureapproximating from 100 to 200 F. and is heated in contact with pebblestherein to a temperature of about 700, to 800 Frcausingf carbonmonoxide-therein to react exothermically `to form carbon black togetherwith carbon dioxide and some water, as discussed hereabove. Totalgaseous efliuentis withdrawn "cussed, or'an'ysuitableseparationmeans.Carbon black thus-separated 'inf zone S7is withdrawn through line' 89.'Residualgasg from 'the'sep'aration in`z`one87 Visdist'sharged fthroughline 91 "and returned through line 925v to-'chamber "l'ift'hroi'1g'hlline2 I2.

A'In-some' instances, dependent 'upon the temperaturecon- The relationofpebble ow to gas ow inthe conversion "f chamber as discussedher'einissubstantially the same Eregardless of Whether'concurrent orcountercurrent flow y'offpeobles and reactant gas is utilized.

yIt'is'to-"be understood that although I have described 'eve'ral'embodiments-of my invention in terms of the useof pebbles, as definedherein, my inventionis not 'limited thereto. ln a-broaderembodime'nt,anycontig'uous mass of owable solid Vparticulate materials caribeutiliz'edhaving a specific*heatfsuitable for absorbing heat 'of'reactionin the conversion chamberjas Ifha've discussed heiiabove lGenerally,-any such'owable solids mass havinga'specitc heat within the limits ffrom0.15A to 0.35 `can=be 'employed in 'the practice of* my inventionQ-andin some1 instances material can be vemployed having ra* spef cificheatoutside thatVr broad range.

Inanother/embodiment, zone 62 can'comprise a'plu- -ral-ityoffzones-inseries or in paraileL'and residue gas 4can'fbe -passedfrom Loneiir1`-heat vexchange"relation Witha smaller vmass of'pebbles'inone of theplurality of pebble fzo'nes. -ehamber'S throught line x1.2 can bepreheated as' required vfor'burningin'ehamberll, While atitiiesametir'ne'steam `or'other cooling'liuidrv can beutilized asrequiredyandfas iliustrate'd@'iniFigure 2, incooling-the-'pebble massinf'ZoneGZ.

Although I 'prefer --to 'utilizea reaction `pressure in '"zonce-'ZS-offrom about-atmospheric tof1'525 p.s. i.' g., higherpressures can beemplyed-if-desired, as for example, from 100 to 400 p. s. i. g. orhigher. Suchv higher Ireaction, i."e.,"the rate of:v conversionof -COtocarbon black, is higher athigherpre'ssures.

'AsV-'Will'fbe eyident-tothose skilled in the art, variousmo'diticationsican be made "or followed, in 'the light of the-:foregoingdisclosure and discussion, withoutdepaiting.1 frornthespirit-or A'seo'peof the disclosure or from Lthe scopefthe claims.

-l. A process'fo'rthemannfacture of'carbon b1aek,'co'm- `strewn-ofca'rbn dioxide and hydrogen 'described hereafter-,iimproportions to formcarbon monoxide ata -tem- A"pe'iat-iire ofro'm 2000 to `3000 F. when theresulting vkadinix ure Sburnedg'burning said admxture, whereby acombustion gas 'mixture' is yformed ct'nnprising carbon vmonoxideghydroge'moarbondioxide, and steam; quenchfi-ngis'aidonibustiongas' mixture tOIaItenipera't ithin :in mit "'f-isuoftetzew1F.,'whereby-menen nlmonoxide'infsaid eonibu'stion "ga maintained `at maixtu xirnum; cooling I the vquenched eomln this '-manner, gas-to berecycled to res-'areparticularlyadvantageoussince 'the rate of Zit)fbu'stion gas `mixture f to i a temperature wit-hin the' limits 'o'fSOtotl'qiFandf removing Waterv and Yicar'bcjrldioxide if omAthe*cooledgasygravitationally"-passi11gl al contiguous mass o'pebbiesifrema'source'hereafter describedthrough aieonversionzone'at aninitialpebbleinlet temperature ywithin-the llimits of 30G to 760'F.,l'and 'passing said `Acooledcombustiongas freed of carbon Vdioxideand water through'said chamber concurrently with said pebble mass4therein,whereby said combustion gas is healed and carbonmonoxideither'einreacts exotliermically tofor'm carbon Lblack togetherwith-carbon dioxide; maintaining "a weight -ratioofp'ebblestogas-introduced into'said conversion zone within-the limits of 8:1 to15:1., whereby-pebbles `insaid-conversion-zone absorb heat liberatedfrom said -exothermic reaction to maintain the'te'mperature' of: saidreaction below L29-0 F.; discharging heated pebblesand total gaseousetiluentfrom said conversion zone'into a pebble-gaseousefuent'separation Zone and therein separating pebbles from said totalgaseouseiuent; said total gaseous ettluent comprising a mixture ofhydrogemcarbon dioxide, and carbon black suspended therein; coolingtotallgaseousetlluent' thus separated by mixing same in heat exchangerelationwtih a cooler stream of carbon dioxide and-"hydrogen ydescribedhereafter, and passing the resulting admixture to a carbon blackseparation z'one and thereiniseparating theiast said admixture intocarbon hiacl; and total residual` gas, said total residualu gascomprisinghydrogenandcarbon dioxide;` cooling at least afportion'ot-saidiesidualgas to a temperature within the fiirnits of 10G'to 200 F.; passing pebbles from said pebbletotalgaseousfeiiiuem'separation zoneto a' pebble cooling -2ene disposed-abovesaid conversion'zone, passing a por- -tienfef--cooled residual gasthrough said-pebblev cooling 'chamber in heat exchange relation withpebbles therein 'tocoolsaid pebblesto'a temperature within'the limitsyof SSG to 700 5F.,`said pebbleA cooling zone being the sourceabove-described of pebbles introduced into 'said conversion chamber;from said-pebble cooling zone with- `drawing a stream orf" said residual-gas heated therein in 'heatex'cha-nge relation with hotterpeb'oles'andadmixing the withdraw-n residual gas with said oil and oxygen`as'saidfstream oicarbon dioxide and hydregempassing la portion of saidcooled residual' gas as said cooler stream etfcarbon dioxide andhydrogen with total gaseous effluent as described; and recovering'carbon black from said earbon black separation zone.

f2. Thelproce'ss of claim vl wherein aportion'ofsaid residual gasseparated in said carbon black separation'zone isfrecycled lwithoutcooling `as a portionof'said stream 'oi-carbon dioxide andhydrogen'admixe'd with said'oil fandf'oxyg'en. Y

3. 'A process for the manufacture of carbon black, comprising admixinga. hydrocarbon oil with oxygenand la "streamof'carbon dioxide andhydrogendes'cribed here- Vafter,in"pror'nortions to form carbon monoxide-atfa temper'ature of-.from 2000 to 3000" F. -wh'en theresultin'g-fadmi'x'ture is burned; burning saidadmixture,` Whereby'a Lcombustiongasmixture is formed comprising carbon monoxide, hydrogen, carbondioxide,`and steam; quenching said combustion -gas mixture to-a'temperature within the limits of 80G to i200 F., wherebythefconcentration of carbon monoxide in said-combustion gas mixture is*maintainedfat a maximum; cooling the quenched'eo'mibn'st'ion V'gas-niixture 'to a temperature \vithin"tlie limits A'ot' 50l to"200 F.' andremoving .va'ter-andfcarbon'dioxide 'from'the cooled gas;gravitationaiiy passing a contiguous l'mass ofpebbles from a sourcehereafter described to a conversion zone at an initial pebble inlettemperature 'within the limitsof 3U() yto 700 F., and'passing-saidcooledcornbustion-gas freed of carbon dioxide and water throughsaidchamberconcurrently with said pebble -ma'ss t-nei'ein ,whereby 4saidCombustion: gas =is` heated-ancicarbon monoxide therein reactsexothermiiallytoformLearlonibleko'get-her"'Witl'tcai'bonl-diox-idefmaintaining Weight ratio Tof.;pebbles -to Agris iiitro'ducedliiito mim-conversin zone within thelimits of 8:1 to 15:1, whereby pebbles in said conversion zone having asuiciently high heat capacity absorb heat liberated from said exothermicreaction to maintain the temperature of said reaction below 1200 F.;discharging heated pebbles and total gaseous eiuent from said conversionzone; said total gaseous eiuent comprising hydrogen, carbon dioxide,steam, and carbon black suspended therein, separating steam and carbonblack from said total gaseous etiluent to provide a residual gascomprising hydrogen and carbon dioxide; recycling residual gas thusseparated in admixture with said hydrocarbon oil and oxygen as saidstream of carbon dioxide and hydrogen described hereabove; passingpebbles thus separated to a pebble cooling chamber disposed above saidconversion chamber and passing a cooler gas through said pebble coolingchamber in heat exchange relation with pebbles to cool same to atemperature within the range of 300 to 700 F.; said pebble coolingchamber being the source of pebbles introduced into said conversionchamber as described above; and recovering carbon black as a product ofthe process.

4. A process for the manufacture of carbon black comprising admixing ahydrocarbon oil with oxygen and a stream of carbon dioxide and hydrogendescribed hereafter, in proportions to form carbon monoxide at atemperature Within the limits of 2000 to 3000 F.; gravitationallypassing a contiguous mass of pebbles through a iirst pebble zone, asecond pebble zone disposed below said tirst pebble zone, and a lthirdpebble zone disposed below said second pebble zone; burning the oiladmixture formed as above described, whereby combustion gas is formedcomprising carbon monoxide, hydrogen, carbon dioxide, and steam;quenching said combustion gas to a temperature within the limits of 800to 1200 F. by passing same through said rst pebble zone in contact withpebbles introduced thereinto at a temperature below 1200" F. asdescribed hereafter, whereby the concentration of carbon monoxide insaid combustion gas is maintained at a maximum; cooling the quenchedcombustion gas to a temperature within the limits of 50 to 200 F. andremoving water and carbon dioxide from the cooled gas; cooling pebblespassed from said first pebble zone into said second pebble zone in heatexchange relation with a cooler gas as described hereafter, to atemperature within the limits of 300 to 700 F.; passing said cooledcombustion gas through said third pebble zone in counter current owrelation with pebbles therein previously cooled in said second pebblezone, whereby said combustion gas is heated and carbon monoxide thereinreacts exothermically to form carbon black together'with carbon dioxide;maintaining a weight ratio of pebbles to gas introduced into said thirdpebble zone within the limits of 8:1 to 15:1, whereby pebbles in saidthird pebble zone having a high specic heat absorb heat liberated fromsaid exothermic reaction to maintain Vthe maximum temperature of saidreaction below l200 F.; discharging pebbles lfrom said third pebble zoneat said temperature below 1200" F. and passing the discharged pebblesinto said first pebble zone; passing total gaseous efiiuent from saidthird pebble zone, said gaseous etiuent comprising hydrogen, carbondioxide, and carbon black suspended therein; cooling said gaseousetiiuent to a temperature below that of said pebbles introduced intosaid third pebble zone and passing the cooled eiuent mixture to a carbonblackv separation zone, and therein separating same into carbon blackand total ridue gas, said :total residue gas comprising carbon dioxideand hydrogen; withdrawing said residual gas from said carbon blackseparation zone and passing at least a portion of same through saidsecond pebble zone in said heat exchange relation therein describedabove; from said second pebble zone withdrawing a stream of saidresidual gas heated therein in said heat exchange, and admixing samewith said oil and oxygen as said stream of carbon dioxide and hydrogen;and recovering carbon black from said carbon black separation Zone.

5. The process of claim 4 wherein a portion of residual gas withdrawnfrom said carbon black separation zone is admixed directly with said oiland oxygen as a part of said stream of carbon dioxide and hydrogen.

References Cited in the tile of this patent UNITED STATES PATENTS1,446,933 Schnee Feb. 27, 1923 1,964,744 Odell July 3, 1934 2,389,636Ramseyer Nov. 27, 1945 2,423,527 Steinschlaeger July 8, 1947 2,432,520Ferro Dec. 16, 1947 2,486,879 Rees et al. Nov. 1, 1949 2,526,652v GarboOct. 24, 1950

1. A PROCESS FOR THE MANUFACTURE OF CARBON BLACK, COMPRISING ADMIXING AHYDROCARBON OIL WITH OXYGEN AND A STREAM OF CARBON DIOXIDE AND HYDROGENDESCRIBED HEREAFTER, IN PROPORTIONS TO FORM CARBON MONOXIDE AT ATEMPERATURE OF FROM 2000 TO 3000* F. WHEN THE RESULTING ADMIXTURE ISBURNED; BURNING SAID ADMIXTURE, WHEREBY A COMBUSTION GAS MIXTURE ISFORMED COMPRISING CARBON MONOXIDE, HYDROGEN, CARBON DIOXIDE, AND STEAM;QUENCHING SAID COMBUSTION GAS MIXTURE TO A TEMPERATURE WITHIN THE LIMITSOF 800 TO 1200* F., WHEREBY THE CONCENTRATION OF CARBON MONOXIDE IN SAIDCOMBUSTION GAS MIXTURE IS MAINTAINED AT A MAXIMUM; COOLING THE QUENCHEDCOMBUSTION GAS MIXTURE TO A TEMPERATURE WITHIN THE LIMITS OF 50 TO 200*F. AND REMOVING WATER AND CARBON DIOXIDE FROM THE COOLED GAS;GRAVITATIONALLY PASSING A CONTIGUOUS MASS OF PEBBLES FROM A SOURCEHEREAFTER DESCRIBED THROUGH A CONVERSION ZONE AT AN INITIAL PEBBLE INLETTEMPERATURE WITHIN THE LIMITS OF 300 TO 700* F., AND PASSING SAID COOLEDCOMBUSTION GAS FREED OF CARBON DIOXIDE AND WATER THROUGH SAID CHAMBERCONCURRENTLY WITH SAID PEBBLE MASS THEREIN, WHEREBY SAID COMBUSTION GASIS HEATED AND CARBON MONOXIDE THEREIN REACTS EXOTHERMICALLY TO FORMCARBON BLACK TOGETHER WITH CARBON DIOXIDE; MAINTAINING A WEIGHT RATIO OFPEBBLES TO GAS INTRODUCED INTO SAID CONVERSION ZONE WITHIN THE LIMITS OF8:1 TO 15:1, WHEREBY PEBBLES IN SAID CONVERSION ZONE ABSORB HEATLIBERATED FROM SAID EXOTHERMIC REACTION TO MAINTAIN THE TEMPERATURE OFSAID REACTION BELOW 1200* F., DISCHARGING HEATED PEBBLES AND TOTALGASEOUS EFFLUENT FROM SAID CONVERSION ZONE INTO A PEBBLE-GASEOUSEFFLUENT SEPARATION ZONE AND THEREIN SEPARATING PEBBLES FROM SAID TOTALGASEOUS EFFLUENT; SAID TOTAL GASEOUS EFFLUENT COMPRISING AN MIXTURE OFHYDROGEN, CARBON DIOXIDE, AND CARBON BLACK SUSPENDED THEREIN; COOLINGTOTAL GASEOUS EFFLUENT THUS SEPARATED BY MIXING SAME IN HEAT EXCHANGERELATION WITH A COOLER STREAM OF CARBON DIOXIDE AND HYDROGEN DESCRIBEDHEREAFTER, AND PASSING THE RESULTING ADMIXTURE TO A CARBON BLACKSEPARATION ZONE AND THEREIN SEPARATING THE LAST SAID ADMIXTURE INTOCARBON BLACK AND TOTAL RESIDUAL GAS, SAID TOTAL RESIDUAL GAS COMPRISINGHYDROGEN AND CARBON DIOXIDE; COOLING AT LEAST A PORTION OF SAID RESIDUALGAS TO A TEMPERATURE WITHIN THE LIMITS OF 100 TO 200* F., PASSINGPEBBLES FROM SAID PEBBLETOTAL GASEOUS EFFLUENT SEPARATION ZONE TO APEBBLE COOLING ZONE DISPOSED ABOVE SAID CONVERSION ZONE, PASSING APORTION OF COOLED RESIDUAL GAS THROUGH SAID PEBBLE COOLING CHAMBER INHEAT EXCHANGE RELATION WITH PEBBLES THEREIN TO COOL SAID PEBBLES TO ATEMPERATURE WITHIN THE LIMITS OF 300 TO 700* F., SAID PEBBLE COOLINGZONE BEING THE SOURCE ABOVE DESCRIBED OF PEBBLES INTRODUCED INTO SAIDCONVERSION CHAMBER; FROM SAID PEBBLE COOLING ZONE WITHDRAWING A STREAMOF SAID RESIDUAL GAS HEATED THEREIN IN HEAT EXCHANGE RELATION WITHHOTTER PEBBLES AND ADMIXING THE WITHDRAWN RESIDUAL GAS WITH SAID OIL ANDOXYGEN AS SAID STREAM OF CARBON DIOXIDE AND HYDROGEN, PASSING A PORTIONOF SAID COOLED RESIDUAL GAS AS SAID COOLER STREAM OF CARBON DIOXIDE ANDHYDROGEN WITH TOTAL GASEOUS EFFLUENT AS DESCRIBED; AND RECOVERING CARBONBLACK FROM SAID CARBON BLACK SEPARATION ZONE.